This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. To assess body composition, bone density, pulmonary function and fitness levels in a large cohort of healthy children. While others have compiled individual data (i.e. body composition or fitness) on large cohorts this would be a novel investigation of relationship between these many developmental parameters within a single group of healthy children.